JComboBoxes

Hi all
I am working on a UI which has 2 tabs.In the class for the first tab I declare and initialize an array of JComboBoxes.
public class tabone{
protected JComboBox[] combolist = new JComboBox[3];
public addComponents(){
for(int i=0;i<4;i++)
{
this.combolist[i] = new JComboBox();
}
//set name for JcomboBoxes
combolist[0].setName("combo1");
combolist[1].setName("combo2");
combolist[2].setName("combo3");
combolist[3].setName("combo4");
}
}

In the class for the second Tab I want to access the last two JComboBoxes.
These two claases are in the same package.
public class tabtwo extends tabone{String name = combolist[2].getName();
This line throws up an error:Exception in thread "main" java.lang.NullPointerException

Can someone please tell why i am getting this error.
or
How should I access the JComboBoxes in the class for tabtwo?

Hi
Thanks for the solution Hardwired.It works.:)
In continuation of the same UI program ..I have a few more Queries.
ComboBox[2] is present in tab2. The list for this combobox2 depends on the
value selected in combobox[1] which is present in tab1.
I have added an action listener on combobox1 .when the user selects the value, I get the list to be loaded for combobox2 in the form of a vector.
But I am not able to put this in the list for combobox2.that is i am not able to view it in the UI.The list for combobox2 remains blank

here is what I do:

listforcombo---is the vector that has to be loaded into combobox2
listforcombo = listofindevars.findependentValues(frameText,var_na me,frameText,(String) dependentVars.elementAt(i));